Such wings with retractable wing end pieces are known, and used, for example, in wings of aircraft transported on aircraft carriers. In order to ensure that the aircraft require as little space as possible while parking the aircraft, during so-called hangaring, the wing tips are folded up, thereby reducing the extension of the aircraft in its wingspan direction. The known systems here comprise simple flap mechanisms, for example which fold up via hinges around a single rotational axis of the wing end piece relative to the main wing in a folding motion, i.e., can be retracted. When used in an aircraft during flight, the wing end piece is folded out along this single rotational axis via the hinge in the folding motion, and brought into its flight position. Both folding processes are usually performed manually or with mechanical aids by the ground personnel, and are usually followed by a locking process after the wing end pieces have been folded out. Locking is necessary to ensure safe flight operations, in particular to prevent unintentional retraction of the wing end pieces during flight.
The disadvantage to the known systems lies precisely in the simple configuration of the folding mechanism, which requires that the folding motion be performed manually. The outlay for automating such a folding mechanism is very high, since retraction takes place over a relatively long path of the wing end piece. At least during the folding process, this yields extremely unfavorable leverage ratios, the negotiation of which necessitates that a high level of force be applied by an actuator. As a consequence, a complicated, and hence expensive, actuator would be required on the one hand, along with a reinforced configuration of the folding kinematics on the other. Aside from the higher manufacturing costs, this leads to a higher weight of the components, and hence to a lower efficiency in aircraft operation.
However, it may be advantageous or even necessary in special situational applications for the folding motion to take place automatically. In particular for both retraction and extension of the wing end piece to be performed automatically. For example, this holds true when the aim is to land large aircraft, in particular aircraft with large wingspan dimensions for load transports or intercontinental connections, at relatively small airports. While large aircraft can also land at relatively small airports depending on the length of the landing strip, small airports are often limited with respect to the maximum wingspan of the aircraft maneuvering thereupon. In addition to the widths and thickness of taxiways on the maneuvering area, attention must also be focused on the parking positions, in particular on the so-called fingers of an airport terminal. Therefore, it would basically be helpful to use foldable wing end pieces, but only in a configuration ensuring that the wing end pieces are folded out immediately as the aircraft exits the landing strip after landing, or only after it reaches the runway just before takeoff, so that the full wingspan is only established on the takeoff and landing strip.